The medical complexity of patients presenting to clinicians is increasing, and that complexity has made preventive care and disease management more complicated (1). This complexity is illustrated in cardiovascular disease (CVD), the leading cause of mortality in the US. (2) Patients with CVD or with CVD risk factors, such as hypertension (HTN), elevated cholesterol, and diabetes (DM), are medically complex, requiring lifestyle modification, medications, periodic testing for complications of disease, and monitoring of medications. The Chronic Care Model provides an approach to medically complex patients that emphasizes the use of health information technology and patient self-management (3). To assist with patient self management, there is growing interest in personal health records (PHRs) integrated with providers'electronic medical records (EMRs), but there have been few studies to evaluate this. (4) The University of Pittsburgh Medical Center health system (UPMC-HS) has deployed an integrated PHR at many primary care sites, which allows patients to view portions of their EMR including the problem list, medications, allergies, health reminders, and test results and to send secure electronic messages to the primary care physician's (PCP) office. This project seeks to improve health care outcomes in complex patients with CVD or who are at high risk for developing CVD by promoting patient self-management. This will be accomplished in 4 diverse, large primary care practices through the following 3 aims: (1) develop a patient-specific, active component to an existing electronic PHR directed towards patients with complex illnesses that is designed to reduce the risk of cardiovascular disease, (2) conduct a randomized controlled trial of the effectiveness of passive and active PHRs for improving adherence and clinical outcomes of complex patients in an ambulatory environment, and (3) enumerate the barriers and facilitators to implementation and use of an PHR among providers and patients in an ambulatory setting. To accomplish the aim 1, a users group will be assembled to determine which potential features of an 'active PHR'would be most acceptable and useful to them. To accomplish the 2nd aim, 1,000 patients with complex chronic disease leading to increased cardiovascular risk (i.e., CVD or 2 of the 4 conditions of HTN, DM, or hyperlipidemia requiring at least one medication for control) will be randomized to a passive PHR (n=500), or an active PHR (n=500) at 4 sites where the PHR currently is installed and in use. Outcomes to be assessed include improvement in control of risk factors (e.g., blood pressure), frequency of compliance with testing guidelines (e.g., annual dilated retinal exams in DM), and clinical outcomes (e.g., myocardial infarction, hospitalizations). Aim 3 will be accomplished by surveying all participants using the PHR, along with nurses and physicians at the study sites, and by conducting focus groups of PHR participants, nurses, and physicians to determine the most useful features of the PHR and to barriers and facilitators of use.